Current limiters find widespread use in energy technology and in electric power production. In energy technology in general and in high-voltage technology in particular, the most well-known current limiters are those that function using choke coils according to the principle of the shielded iron core or of the direct current pre-magnetized iron core. A drawback of current limiters that make use of iron cores is that they are characterized by a high volume and great weight, as well as by the relatively high impedance of the electric system during operation at nominal value.
Current limiters referred to as Is limiters are also known. The advantage of these Is limiters is that the impedance during normal operation is negligible low, but can be abruptly increased in case of a fault. This can be achieved by employing detonating caps. A drawback of this system, however, is that the use of detonating caps calls for a maintenance procedure every time they are triggered, and that it can only be scaled to a limited extent for applications in high-voltage technology.
Another approach is the use of superconducting materials. German specification DE 60 2004 012035 describes, for example, a superconducting current limiter with a magnetic field-assisted quench. In case of a fault, the current flowing through the superconductor gives rise to a critical current and the superconductor switches over to the normal-conductive state. According to the current limiter disclosed in German specification DE 60 2004 012035, each superconductor element is connected in parallel to a coil.
Another known principle is that of the so-called resistive superconducting current limiters whose non-linear current-voltage line limits the current in case of a short circuit. A drawback of the two latter principles is that the power has to be supplied by means of suitable means between a room-temperature environment and a low-temperature environment. This causes high thermal losses.